Sonoactivated Cascade Fenton Reaction Enhanced by Synergistic Modulation of Electron-Hole Separation for Improved Tumor Therapy.

Chemodynamic therapy (CDT) is an emerging targeted treatment technique for tumors via the generation of highly cytotoxic hydroxyl radical (·OH) governed by tumor microenvironment-assisted Fenton reaction. Despite high effectiveness, it faces limitations like low reaction efficiency and limited endogenous H2 O2 , compromising its therapeutic efficacy. This study reports a novel platform with enhanced CDT performance by in situ sono-activated cascade Fenton reaction. A piezoelectric g-C3 N4 (Au-Fe-g-C3 N4 ) nanosheet is developed via sono-activated synergistic effect/H2 O2 self-supply mediated cascade Fenton reaction, realizing in situ ultrasound activated cascade Fenton reaction kinetics by synergistic modulation of electron-hole separation. The nanosheets consist of piezoelectric g-C3 N4 nanosheet oxidizing H2 O to highly reactive H2 O2 from the valence band, Fe3+ /Fe2+ cycling activated by conduction band to generate ·OH, and Au nanoparticles that lower the bandgap and further adopt electrons to generate more 1 O2 , resulting in improved CDT and sonodynamic therapy (SDT). Moreover, the Au-Fe-g-C3 N4 nanosheet is further modified by the targeted peptide to obtain P-Au-Fe-g-C3 N4 , which inhibits tumor growth in vivo effectively by generating reactive oxygen species (ROS). These results demonstrated that the sono-activated modulation translates into a high-efficiency CDT with a synergistic effect using SDT for improved anti-tumor therapy.

An evaluation index system for regional mobile SARS-CoV-2 virus nucleic acid testing capacity in China: a modified Delphi consensus study.

BACKGROUND: Large-scale detection has great potential to bring benefits for containing the COVID-19 epidemic and supporting the government in reopening economic activities. Evaluating the true regional mobile severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus nucleic acid testing capacity is essential to improve the overall fighting performance against this epidemic and maintain economic development. However, such a tool is not available in this issue. We aimed to establish an evaluation index system for assessing the regional mobile SARS-CoV-2 virus nucleic acid testing capacity and provide suggestions for improving the capacity level. METHODS: The initial version of the evaluation index system was identified based on massive literature and expert interviews. The Delphi method questionnaire was designed and 30 experts were consulted in two rounds of questionnaire to select and revise indexes at all three levels. The Analytic Hierarchy Process method was used to calculate the weight of indexes at all three levels. RESULTS: The evaluation index system for assessing the regional mobile SARS-CoV-2 virus nucleic acid testing capacity, including 5 first-level indexes, 17 second-level indexes, and 90 third-level indexes. The response rates of questionnaires delivered in the two rounds of consultation were 100 and 96.7%. Furthermore, the authority coefficient of 30 experts was 0.71. Kendall's coordination coefficient differences were statistically significant (P < 0.001). The weighted values of capacity indexes were established at all levels according to the consistency test, demonstrating that 'Personnel team construction' (0.2046) came first amongst the five first-level indexes, followed by 'Laboratory performance building and maintenance' (0.2023), 'Emergency response guarantee' (0.1989), 'Information management system for nucleic acid testing resources' (0.1982) and 'Regional mobile nucleic acid testing emergency response system construction' (0.1959). CONCLUSION: The evaluation system for assessing the regional mobile SARS-CoV-2 virus nucleic acid testing capacity puts forward a specific, objective, and quantifiable evaluation criterion. The evaluation system can act as a tool for diversified subjects to find the weak links and loopholes. It also provides a measurable basis for authorities to improve nucleic acid testing capabilities.

Factors Associated With the Vaccination Behavior Among COVID-19 Vaccine Hesitant College Students in Wuhan, China: A Survey Based on Social Psychological Dimension.

Background: During the COVID-19 pandemic, vaccine hesitancy (VH) on COVID-19 vaccination still exists in different populations, which has a negative impact on epidemic prevention and control. The objectives were to explore college students' willingness to vaccinate, determine the factors influencing the vaccination behavior of students with COVID-19 vaccine hesitancy, and provide a basis for improving the compliance of college students with COVID-19 vaccination. Methods: The universities in Wuhan are categorized into three levels according to their comprehensive strength and randomly sampled at each level, of which ten universities were selected. A self-designed anonymous electronic questionnaire was distributed online from May 12 to 31, 2021 to investigate the hesitancy, vaccination status, and influencing factors of COVID-19 vaccination among college students in Wuhan. Results: Of the 1,617 participants (1,825 students received the electronic questionnaire) surveyed, 19.0% reported COVID-19 vaccine hesitancy. Among the vaccine-hesitant students, 40.1% were vaccinated against COVID-19. The binary logistic regression analysis shows that families' attitudes "Uncertain" (odds ratio (OR) = 0.258 [0.132-0.503]), vaccination risk psychology (OR = 0.242 [0.079-0.747]) and wait-and-see mentality (OR = 0.171 [0.068-0.468]) are negative factors for the vaccination behavior of hesitant students, while herd mentality (OR = 7.512 [2.718-20.767]) and uncertainty of free policy's impact on vaccine trust (OR = 3.412 [1.547-7.527]) are positive factors. Conclusion: The vaccine hesitancy among college students in Wuhan was relatively high. Family support, herd mentality and free vaccination strategies can help improve vaccination among hesitant students, while vaccination risk psychology and "wait-and-see" psychology reduce the possibility of vaccination. The vaccination strategy of college students should be strengthened from the perspective of social psychological construction.

Association Between Water Intake and Mortality Risk-Evidence From a National Prospective Study.

Background: Few studies have explored the association between water intake and mortality risk, and the findings were inconsistent. Objective: This study aimed to explore the water intake-mortality association, utilizing the data from the National Health and Nutrition Examination Survey (NHANES) and the 2015 public-linked mortality files released by the National Center for Health Statistics. Methods: We used the diet- and mortality-linked data of a total of 35,463 adults (17,234 men) aged ≥20 years in the NHANESs 1999-2014 to perform a prospective study. The multivariate-adjusted Cox proportional hazards model was used to explore the associations of the amount of water intake (expressed by total water, plain water, beverage, and food water) and water intake proportion (expressed by the percentage of each kind of water) with mortality risks due to all causes, malignant neoplasms/cancer, and heart disease. The restricted cubic spline plots were adopted to clarify the dose-response relationships among them. Results: With a median of 88 months (interquartile range: 49-136 months) follow-up, a total of 4,915 all-cause deaths occurred, including 1,073 and 861 deaths from malignant neoplasms/cancer and heart disease, respectively. The amount of water intake in either type was negatively associated with all-cause mortality risk. Additionally, the negative linear dose-response relationships of water intake and all-cause mortality risk were found for all types of water except for food water, which followed a non-linear pattern. Similarly, compared to the lowest quartile (beverage water intake: <676 g/day; food water intake: <532 g/day), beverage and food water intakes in the range of 1,033-1,524 and 1,612-3,802 g/day were associated with decreased malignant neoplasms/cancer mortality risk. A U-shaped dose-response relationship was found for beverage water intake and malignant neoplasms/cancer mortality risk and a negative linear dose-response relationship was found for food water intake and malignant neoplasms/cancer mortality risk. Coffee and/or tea consumption was/were negatively associated with mortality risks due to all causes and malignant neoplasms/cancer. No significant associations of water intake proportion and mortality risks were found. Conclusion: Our findings demonstrated that higher water intake is associated with lower mortality risks among the United States population.

Controlled release of drug molecules by pillararene-modified nanosystems.

Stimuli-responsive nanosystems have attracted the interest of researchers due to their intelligent function of controlled release regulated by a variety of external stimuli and have been applied in biomedical fields. Pillar[n]arenes with the advantages of a rigid structure, electron holes and easy functionalization are considered as excellent candidates for the construction of host-guest nanosystems. In recent years, many pillararene modified nanosystems have been reported in response to different stimuli. In this feature article, we summarize the advance of stimuli-responsive pillararene modified nanosystems for controlled release of drugs from the perspectives of decomposition release and gated release, focusing on the control principles of these nanosystems. We expect that this review can enlighten and guide investigators in the field of stimuli-responsive controlled release.

Multiple vitamin co-exposure and mortality risk: A prospective study.

BACKGROUND & AIMS: Existing epidemiological studies explored the associations of circulating vitamins and mortality focusing on individual vitamin effects, and controversial findings were obtained. The joint effects of multiple vitamin co-exposure are worth studying. The study aimed to elucidate the associations of circulating vitamins and the joint effects of these vitamins' co-exposure with all-cause and cause-specific mortality risks. METHODS: We prospectively evaluated the associations of the concentrations of six kinds of vitamins (A, D, E, C, B12 and B9) in serum with risks for all-cause and cause-specific mortalities among U.S. adults. Mortality status and cause of death were determined by NHANES-linked public available files dated up to 31 December 2015. An unsupervised K-means clustering method was used to cluster the participants into several vitamin co-exposure patterns. The Cox proportional hazards model was used for statistical analysis. RESULTS: A total of 1404 deaths occurred during a median of 10.9 years follow-up among 8295 participants. In multivariable adjustment, increasing levels of vitamin D were associated with reduced all-cause and cause-specific mortality risks. A J-shaped nonlinear exposure-response relationship was observed between all studied vitamins (except for vitamin D) and all-cause mortality risk. Four co-exposure patterns were generated based on the studied vitamins, as follows: low-level exposure (cluster 1), vitamin A/D exposure (cluster 2), water-soluble vitamin exposure (cluster 3) and high-level exposure (cluster 4). Compared with those in cluster 1, participants in cluster 2 had lower all-cause and cancer mortality risks, with hazard ratios (95% confidence intervals [CIs]) of 0.67 (0.53, 0.85) and 0.45 (0.29, 0.71), respectively. CONCLUSIONS: The findings in this study indicated that high circulating vitamin D levels were associated with reduced mortality risk among U.S. adults. Vitamin co-exposure at moderate levels appropriately contributed to low all-cause and cancer mortality risks. Our findings provided a novel perspective for exploring the joint health effects of multivitamin co-exposure. Future investigations are needed to further unravel the underlying mechanisms of possible vitamin interactions.

Maternal smoking status during pregnancy and low birth weight in offspring: systematic review and meta-analysis of 55 cohort studies published from 1986 to 2020.

BACKGROUND: Maternal smoking during pregnancy may be associated with low birth weight (LBW) in offspring and global risk estimates have not been summarized previously. We aimed to systematically explore evidence regarding maternal smoking and the LBW risk in offspring globally and examine possible causes of heterogeneity across relevant studies. METHODS: Comprehensive search of PubMed, Ovid Embase, Ovid Medline (R), and Web of science from inception until October 2021 was carried out. A random-effects meta-analysis was used to estimate the pooled odds ratio (OR) and corresponding 95% confidence interval (CI). Restricted cubic spline analysis with three knots was used to further examine the dose-response relationship. RESULTS: Literature searches yielded 4940 articles, of which 53 met inclusion criteria (comprising 55 independent studies). Maternal smoking during pregnancy was significantly associated with the risk of LBW in offspring (OR = 1.89, 95% CI = 1.80-1.98). Furthermore, an obvious dose-response relationship between the amount of cigarettes daily smoked in pregnancy and the risk of LBW in offspring was observed. The results of subgroup analyses indicated that the risk of maternal smoking on LBW was larger in more recently conducted studies (P = 0.020) and longer period of active smoking during pregnancy (P = 0.002). No evidence of publication bias was found. CONCLUSIONS: In summary, maternal smoking in pregnancy was significantly associated with a higher risk of LBW in offspring on a global scale. The risk of maternal smoking on infant LBW seems to be increasing over time, and was higher with longer smoking duration throughout pregnancy and more cigarettes smoked daily.

Association between long-term exposure to PM2.5 and hypertension: A systematic review and meta-analysis of observational studies.

BACKGROUND: Numerous studies have examined the association between long-term exposure to particulate matter with an aerodynamic diameter of ≤2.5 µm (PM2.5) and hypertension. However, the results are inconsistent. OBJECTIVES: Considering the limitations of previous meta-analyses and the publication of many new studies in recent years, we conducted this meta-analysis to assess the relationship between long-term PM2.5 exposure and the incidence and prevalence of hypertension in a healthy population. METHODS: We searched PubMed, Web of Science, Embase, and Scopus for relevant studies published until April 2, 2021 and reviewed the reference lists of previous reviews. A total of 28 observational studies reporting RR or OR with 95% CI for the association between long-term PM2.5 exposure and the risk of hypertension were included. RESULTS: After the sensitivity analysis, we excluded one study with a high degree of heterogeneity, resulting in 27 studies and 28 independent reports. Approximately 42 million participants were involved, and the cases of hypertension in cohort and cross-sectional studies were 508,749 and 1,793,003, respectively. The meta-analysis showed that each 10 µg/m3 increment in PM2.5 was significantly associated with the risks of hypertension incidence (RR = 1.21, 95% CI: 1.07, 1.35) and prevalence (OR = 1.06, 95% CI: 1.03, 1.09). Subgroup analyses showed that occupational exposure had a significant effect on the association of PM2.5 and hypertension incidence (p for interaction = 0.042) and that the PM2.5 concentration level and physical activity had a noticeable effect on the association of PM2.5 and hypertension prevalence (p for interaction = 0.005; p for interaction = 0.022). CONCLUSIONS: A significantly positive correlation was observed between long-term PM2.5 exposure and risks of hypertension incidence and prevalence, and a high PM2.5 concentration resulted in an increased risk of hypertension.

Associations of multiple metals with bone mineral density: A population-based study in US adults.

Epidemiologic studies focus on combined effects of multiple metals on bone mineral density (BMD) are scarce. Therefore, this study was conducted to examine associations of multiple metals exposure with BMD. Data of adults aged ≥20 years (n = 2545) from the US National Health and Nutrition Examination Survey (NHANES, 2011-2016) were collected and analyzed. Concentrations of metals were measured in blood (cadmium [Cd], lead [Pb], mercury [Hg], and manganese [Mn]) and serum (copper [Cu], selenium [Se], and zinc [Zn]) using inductively coupled plasma mass spectrometry and inductively coupled plasma dynamic reaction cell mass spectrometry, respectively. The weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models were performed to determine the joint effects of multiple metals exposure on lumbar and total BMD. The linear regression analyses showed Pb was negatively associated with BMDs. The WQS regression analyses revealed that the WQS index was inversely related to lumbar (ß = -0.022, 95% CI: -0.036, -0.008) and total BMD (ß = -0.015, 95% CI: -0.024, -0.006), and Se, Mn, and Pb were the main contributors for the combined effects. Additionally, nonlinear dose-response relationships between Pb, Mn, and Se and BMD, as well as a synergistic interaction of Pb and Mn, were found in the BKMR analyses. Our findings suggested co-exposure to Cd, Pb, Hg, Mn, Cu, Se, and Zn (above their 50th percentiles) was associated with reduced BMD, and Pb, Mn, and Se were the main contributors driving the overall effects.

Discrepancy in perceived social support and related factors among Chinese college students with and without siblings.

BACKGROUND: Whether there is a difference in perceived social support (PSS) and related factors among college students from one- and multiple-child families was unclear. METHODS: We conducted a population-based, cross-sectional study between October 2017 and February 2018, randomly selected college students with siblings (n=5875; aged 19.41±1.99 years) and their counterparts without siblings (n=5175; aged 19.88±2.38 years), and then conducted an online questionnaire survey via a multi-stage cluster random sampling method. We applied the multidimensional scale of perceived social support (MSPSS) to evaluate PSS among college students. The multivariable logistic regression models were used to predict factors associated with low perceived social support in two student groups. RESULTS: Our study found that there was a statistical difference of PSS between the sibling groups. Sex, single-parent family, irregular daily routine, prevalence of diseases or injuries and psychological distress were significantly associated with low PSS in both college students with and without siblings. Compared with single-child college students, single-parent family structure was associated with a higher odds ratio for low PSS in college students with siblings (ratio of odds ratio: 0.71, 95% confidential interval: 0.53-0.97). LIMITATIONS: Our study was a cross-sectional study design, and all participants in current study were from Wuhan city, Hubei Province. Hence, the sample is not representative of other regions in China. CONCLUSIONS: Although a statistical difference of PSS between the sibling groups was found in our study, single-parent family structure was more strongly associated with low PSS in multiple-child students compared with single-child students.

Estimating the costs of the national basic public health services in Zhuhai, China, through activity-based costing: a cross-sectional study.

OBJECTIVE: Our research aims to estimate the per capita cost of 13 items in the basic public health service (BPHS) project in Zhuhai, China, and provide an economical basis for the improvement of the cost compensation mechanism used by the government. DESIGN: This research is a cross-sectional study. SETTING: A total of 19 primary healthcare facilities (PHFs) in Zhuhai, China, are involved in this research. PARTICIPANTS: A total of 152 participants (114 personnel engaged in BPHS, 19 financial personnel and 19 PHF heads) were included in this study, which was conducted from May 2017 to July 2017. PRIMARY AND SECONDARY OUTCOME MEASURES: We used the activity-based costing model to calculate the cost of providing BPHS in Zhuhai. An analytical hierarchy process was used to determine the difficulty dimension and workload coefficient. RESULTS: The weights of the difficulty dimensions in the provision of BPHS in Zhuhai were 35.04% (coordination of residents), 24.03% (staff workload), 21.36% (complexity of work-related skills) and 19.59% (basic qualities of staff). The average difficulty coefficient of each subproject was 5.28. The actual per capita cost of BPHS provision in 2016 was 97.48 RMB (12.76 EUR), which was higher than the actual standard compensation of 55 RMB (7.2 EUR) in Zhuhai. Immunisation was the most costly among the 13 service items (17.82 RMB or 2.33 EUR per person), whereas the management of tuberculosis was the least costly item (0.57 RMB or 0.07 EUR per person). CONCLUSIONS: Government funds for basic public health services cannot compensate for the actual costs. Accordingly, subsidies should be increased based on the actual per capita cost for sustainable BPHS development. The government should improve the methods used in cost estimation and measures used as the basis for awarding performance incentives.

Evaluation of Need and Distribution of National Essential Medicines List in Village Clinics: A Cross-sectional Study Based on the Perspective of Village Doctors in China.

This study aimed to evaluate the satisfaction of village doctors to essential medicines list (EML) and accessibility of essential medicines (EMs) distribution to improve the implementation of EML in village clinics. A total of 422 village doctors from five counties in three provinces of China were surveyed by questionnaires. Logistic regression analysis was conducted to identify the main factors associated with village doctors' evaluation of EML. The results showed that village doctors had a negative evaluation in satisfaction level of EML to village-based care and accessibility of EM distribution. The government should adjust EML regularly based on the actual health status of local villagers in China and focus on adding appropriate drugs that meet the needs of villagers with chronic disease. The local government should also attach importance to the distribution of EMs and maintain their supply in village clinics.

A Novel Fluorescent Nanoparticle for Sensitive Detection of Cry1Ab Protein In Vitro and In Vivo.

Here, we report the synthesis and characterization of CoFe2O4 doping Ag2S dendrimer-modified nanoparticles (CoFe2O4-Ag2S DMNs) in Cry1Ab protein detection and imaging. The near-infrared Ag2S quantum dots were first prepared by using the thermal decomposition method, followed by modification of the water-soluble quantum dots using the method of solvent evaporation and ligand exchange, and finally the fluorescent magnetic bifunctional nanoparticles were obtained by binding with CoFe2O4. As-prepared CoFe2O4-Ag2S DMNs were characterized by fluorescence (FL) spectroscopy and transmission electron microscopy (TEM). Results showed that Ag2S DMNs could sensitively detect Cry1Ab both in vitro and in vivo. In vitro, the enhanced FL intensity as a function of the concentration is notably consistent with the Langmuir binding isotherm equation in the range of 0-200 ng/mL of Cry1Ab proteins. The detection limit of this method was found to be 0.2 ng/mL. Meanwhile, the fluorescence wavelength was extended to the second near-infrared range (NIR-II, 1.0~1.4 µm), which enables in vivo imaging. This study highlights the importance of NIR QDs doping magnetic materials as a new method to trace Bacillus thuringiensis (Bt) in insects and their potential applications in in vivo NIR tissue imaging.

Quaternary Ammonium Polyamidoamine Dendrimer Modified Quantum Dots as Fluorescent Probes for p-Fluorophenoxyacetic Acid Detection in Aqueous Solution.

The wide use of pesticide p-fluorophenoxyacetic acid has caused the serious environmental contaminant. A novel fluorescent probe for sensitive detection of p-fluorophenoxyacetic acid in aqueous solutions based on 3.0G quaternary ammonium polyamidoamine (PAMAM) dendrimer modified quantum dots (QDs) (PAMAM@QDs) was reported. Through the solvent-evaporation method, quaternary ammonium PAMAM was employed to modify the QDs. Poloxamer 188 was used to improve the solubility and stability. The resultant PAMAM@QDs dispersed well in water. Fluorescence (FL) spectroscopic study showed that the FL intensity of the PAMAM@QDs was enhanced in the presence of p-fluorophenoxyacetic acid. Under optimal conditions, the enhanced FL intensity as a function of concentration matched very well in the range of 1 ~ 200 µg/mL of p-fluorophenoxyacetic acid, while the lower limits of detection were found to be 0.16 µg/mL. These results show that PAMAM@QDs is a promising luminescent probe for the detection of pesticides.

Graphite oxide-dispersed CdTe quantum dots nanocomposite for flexible display luminescent membranes.

A quantum dot (QD) dispersant material was prepared using graphite oxide (GO). Luminescent films were prepared using polyvinyl alcohol as the polymer matrix. First, water-soluble CdTe QDs were prepared by wet chemistry and GO was synthesized using a modified Hummers method. X-Ray diffraction tests showed that the GO reflection peak [001] was 11.9°, which indicates that the d-spacing is 0.7431 nm; atomic force microscopy showed a GO thickness of 200 nm. Fourier transform infrared spectra showed vibrations at 1624 cm-1 for the carbonyl groups, and 3260 cm-1 for the GO samples; the -C-O vibration was at 1320 cm-1 and -COOH, -OH vibrations were at 950 cm-1 . Fluorescent tests showed that pH had an impact on the QD colloidal stability. GO was neutralized before use as the host media for the GO/QDs nanocomposite. The results proved that the resultant nanocomposite is promising for use in brightness enhancement films in flexible displays.

Parity and All-cause Mortality in Women and Men: A Dose-Response Meta-Analysis of Cohort Studies.

To quantitatively assess the association between parity and all-cause mortality, we conducted a meta-analysis of cohort studies. Relevant reports were identified from PubMed and Embase databases. Cohort studies with relative risks (RRs) and 95% confidence intervals (CIs) of all-cause mortality in three or more categories of parity were eligible. Eighteen articles with 2,813,418 participants were included. Results showed that participants with no live birth had higher risk of all-cause mortality (RR= 1.19, 95% CI = 1.03-1.38; I(2) = 96.7%, P < 0.001) compared with participants with one or more live births. Nonlinear dose-response association was found between parity and all-cause mortality (P for non-linearity < 0.0001). Our findings suggest that moderate-level parity is inversely associated with all-cause mortality.

High Sensitivity Bacillus thuringiensis Cry1Ac Protein Detections Using Fluorescein Diacetate Nanoparticles.

A highly sensitive transgenic protein analysis method was proposed here based on fluorescein diacetate (FDA). First, FDA was prepared by the ball mill to harvest the nano-sized organic particles. Further examines showed that the FDA size can be controlled by the speed of centrifugation which can obtain FDA in well-distributed size. Cy3 antibody immobilization tests showed that the proteins can attach onto the FDA particles while keep bioactivities. FDA and Cry1Ac antibody immunoassay tests showed that when the FDA particle was in 150 nm, the linear range was 0.01 ng/L-30 µg/mL. And it has the lower detection limitation of 0.01 ng/L, which is 100 times more sensitive than the ELISA methods. These results indicate that the FDA related immunoassays are the promising approach in the transgenic analysis.

Encapsulation of the ethylene inhibitor 1-Methylcyclopropene by cucurbit[6]uril.

1-Methylcyclopropene (1-MCP) is an excellent safe and commercially available ethylene antagonist for the preservation of horticultural products. However 1-MCP has to be stored in absorbents due to its gaseous and unstable characteristics. In this paper cucurbit[6]uril (CB[6]) was used as the absorbent to encapsulate 1-MCP, and the resultant inclusion complex was characterized by IR, powder X-ray diffraction, thermal analysis, and fluorescent spectra. The effects of encapsulation conditions on the formation of inclusion complex were also investigated. The amount of 1-MCP encapsulated by CB[6] was about 4.5% by weight when the initial concentration of 1-MCP, encapsulation temperature, CB[6] concentration, and encapsulation time were set at 75 mL/L, 20 °C, 30 mM, and 8 h, respectively. Furthermore, the release of 1-MCP from the complex can be realized with different solutions such as sodium bicarbonate, benzoic acid, and distilled water. CB[6] can be used as an excellent absorbent for encapsulation of 1-MCP.

Efficient biosensor interfaces based on space-controlled self-assembled monolayers.

In this paper we demonstrate control over the spacing of surface-modifying probe molecules through the use of labile dendron spacers. During this process, anchor molecules are first adsorbed to a surface, with dendron modifiers attached. Steric interactions of the bulky dendrons control the density of anchor molecules bound to the surface. The dendron branches are subsequently detached from the anchor molecules, and the anchors are chemically modified with probe molecules, resulting in a surface with controlled spacing between probe molecules. Control over this spacing is important when the probe size is small in comparison with the target molecule. This importance is demonstrated for the binding of protein (streptavidin) targets to the probe (biotin) surface. The effect of probe space control on the efficiency of target capture is evaluated by examining the binding of streptavidin to thiolated biotin for a series of mixed monolayers. Surface modification is monitored by Fourier transform infrared reflection absorption spectroscopy (FTIR-RAS). The relative concentration of probe molecules at the surface is measured using X-ray photoelectron spectroscopy (XPS) measurements. Thiolated-biotin surfaces with optimized spacing show an increased capture efficiency for streptavidin relative to surfaces with nonoptimal or no control over probe spacing, as measured by surface plasmon resonance (SPR) spectroscopy. These results are of potential significance for the optimization and fabrication of micro- and nanoarrays used in chemical and biochemical measurements.